Control of deposition profile of plasma CVD hard carbon films on substrates with trenches

We have realized sub-conformal, conformal and anisotropic deposition profiles of Cu in trenches by plasma CVD [1]. Here we report control of deposition profile of carbon films by plasma CVD. Experiments were performed using a H-assisted plasma CVD reactor in which a 28 MHz capacitively-coupled main discharge and a 13.56 MHz inductive-coupled discharge for an H atom source were sustained. Toluene diluted with H2 was supplied at a flow rate of 90 sccm. The total pressure of reactor was 13 Pa. To study dependence of deposition rate on a ratio of ion flux to radical flux, substrates were covered with a piece of mesh of 10-50 mesh/inch at 1-5 mm above the substrates. \textit{Without a mesh} the deposition rates at the top, bottom, and sidewall of a trench of the aspect ratio of 1.2 are 20.4, 16.3, and 3.57 nm/min, whereas the corresponding values are 11.7, 9.17, and 3.31 nm/min \textit{with }a piece of mesh of 14 mesh/inch and 60.8{\%} transparency, set 1 mm above the substrate. The deposition profile can be controlled by the ratio of ion flux to radical flux. [1] K. Takenaka, et al. Pure Appl. Chem. \textbf{77}, 391 (2005).